If 0'<'r'<'1'<'s'<'2, which one is less than 1
I. r/s
II. rs
III. s-r
1) I only
2) II only
3) III only
4) I & II
5 I & III


when you consider a problem like this, in which you are GIVEN INEQUALITIES, you should always CONSIDER THE EXTREMES of the given inequalities.


therefore, it's sufficient to think about, say, 0.1 and 0.9 for r, and 1.1 and 1.9 for s.
statement (i): 0.1/1.1, 0.9/1.1, 0.1/1.9, and 0.9/1.9 are all less than 1, so you're good.
statement (ii): works for (0.1)(1.1), (0.9)(1.1), and (0.1)(1.9), but NOT (0.9)(1.9).
statement (iii): only works for 1.1 - 0.9, doesn't work for any of the other pairs.